Muscovite cries out, by computer, over killing of teen-ager SOVIET MILITARY COUP

The graphic description of the death of a teen-age boy at the barricades in Moscow leaked out of the Soviet Union by electronic computer mail.

The account was in a letter from a man named "Aleksei" who was among the Muscovites who rallied to defend the parliament building.

"Last night, there was the first act of violence in Moscow," he wrote.

"I would like to give my personal witness of this episode."

Svetlana May, a Soviet Jew who emigrated to America in 1988, read the letter on her computer at the John Hopkins University Department of Electrical and Computer Engineering.

She passed it on to The Evening Sun.

May had no doubts about its authenticity.

A dozen similar messages have appeared on her computer in the past two days, mostly written in a kind of phonetically Anglicized Russian.

Aleksei's letter was in an excellent, if unpolished, English.

He wrote that at about 1 a.m. yesterday, he saw a detachment of tanks blocked in an underpass about 300 meters from the parliament building. He did not think they were going to storm the building.

"About three hundreds of people, including myself, rushed to the place where they could hear shooting," he wrote.

"Soldiers were not very aggressive. In three vehicles, they opened the hatchways, looked out from them so the people could speak to them.

"Some people behaved peacefully. I, too, came down to the vehicles with my [placard] and spoke to the soldiers. . . . Things became more dangerous quickly."

Members of another group, "mostly teen-agers," were excited and ready to fight.

One vehicle closed its hatches and tried to shake off "a man or two who were staying on its top."

A dozen boys ran around it, "attacking its armor, although the most serious weapons they had were iron and wooden sticks."

After about a minute one of the boys was shot.

"He was attacking the vehicle from its rear, probably without any weapon," Aleksei wrote.

"Its door opened, probably from inside, and somebody shoot him point-blank to death.

"He fell so that half of the body was inside the vehicle and the feet dragged on the ground. The vehicle continued moving back and forth, people were still attacking it.

"Those on the walls [screamed] 'murders'!"

"After a minute the boys picked up the body which fell out."

The armored vehicle tried to smash its way out of the barricade.

"Some reported later that it crushed two more people," said Aleksei's letter.

"I could not see this from my point, but there was a great danger and a real possibility for this. . . . There was a common hysterics."

The other army vehicles remained quietly where they were.

"A soldier from one of them ran out and raised his hands, appealing to the people and apologizing."

"People throw sticks and stones and apparently Molotov cocktails, starting a fire on the 'aggressive vehicle,' which fired its machine gun into the air."

Aleksei felt powerless with his sign and left for about an hour. When he came back, several members of parliament and "a general organizing the defense of the building" were negotiating with the soldiers and even the excited teen-agers were trying to introduce some order.

The night came to an end quietly and Aleksei returned home at 6 a.m.

"The strangest thing," he marveled, "is how easily, naturally, people find themselves, feel and act, in [this] historical situation -- as if it is an ordinary life."